Which famous images resulted from the Hubble telescope staring intensely at minuscule regions of the sky for hundreds of hours?

Answer

Hubble Deep Field (HDF) and Ultra Deep Field (HUDF)

The efforts involving long exposure times focused on tiny sky regions yielded the groundbreaking Hubble Deep Field (HDF) and the subsequent Ultra Deep Field (HUDF) images.

Which famous images resulted from the Hubble telescope staring intensely at minuscule regions of the sky for hundreds of hours?
galaxiesastronomyuniversecosmosestimation